A majority of air conditioning and refrigeration systems use chlorinated flurocarbons (CFCs) as the working refrigerant fluid. When such systems required repair or servicing, it was not uncommon for the repairman to discharge the refrigerant in the system to the atmosphere. Once the servicing or repairs were completed, new refrigerant was added to the system. Because of recent concerns for the environment, it has become illegal in may countries to discharge CFC refrigerants to the atmosphere. It has also become desirable, and in many cases mandated by law, to reclaim and recycle CFC refrigerants.
Environmental concerns are not the only factor in favor of recycling and reusing refrigerants. In recent years, the cost of refrigerants has escalated drastically, having doubled or tripled in the past decade. For this reason, it is not only desirable to remove the refrigerant from a unit prior to service, but to extract as much refrigerant vapor from the unit as is possible to maximize recovery.
It is also desirable that a refrigerant recovery system be portable. Air conditioning systems are typically located on the roof of a building, and any refrigerant recovery apparatus must be transported to the roof in order to be attached to the air conditioning unit. Some prior refrigerant recovery machines use water or air to cool the refrigerant as it is being removed from the air conditioning unit. Recovery machines which require a source of water for their operation are unusable atop buildings that lack a water supply on the roof. Machines which use air to cool the refrigerant may take a substantially long period to remove the refrigerant from an air conditioning unit since temperatures may be in excess of 100.degree. F. on the roof, imposing a great cooling burden on what must necessarily be a small portable apparatus.
Other known methods of refrigerant recovery use refrigerant from the air conditioning unit itself, cooled by the air conditioning unit, to cool the refrigerant being removed. Obviously, such methods require that the air conditioning unit be operational to remove refrigerant therefrom, and are incapable of removing refrigerant from a poorly operating air conditioning unit, even though such an inoperative unit is the most likely candidate for refrigerant removal. Thus, it is highly desirable that a refrigerant recovery system and method be self contained and operate unassisted by the refrigeration system being serviced. Also, the cooling ability of water- or air-cooled refrigeration systems is constrained, as neither can cool refrigerant below the temperature of the water or air employed as a heat transfer medium.